Virtual Security Zones Alan Altmark IBM Senior Managing z/vm Consultant March 2014
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Agenda Introduction Securing System z hardware A multi-zone network VLANs and traffic separation Enforcing the rules 3
The Myth of Mainframe Security 4
The Reality of Mainframe Security 5
Securing the Hardware 6
z/vm Security begins with System z security Protect the HMC Don t share user IDs but don t be afraid to connect it to your internal network Limit span of control as ropriate; add roles Protect the I/O configuration Create a separate LPAR that is authorized to modify the I/O configuration Give partitions access only to devices they require 7
System z Hardware Security LPAR 1 LPAR 2 LPAR 3 z/vm production z/os production Dynamic I/O configuration management authority Minimal z/os or z/vm PR/SM I/O device access is controlled by PR/SM Ethernet HiperSockets 8
Warning: Shared Open Systems Adapters LPAR 1 LPAR 3 LPAR 2 Application Zone Application Zone Data Zone PR/SM? A shared OSA creates a short circuit between LPARs unless QDIO data connection isolation is used (z10 and later) 9
Warning: HiperSockets LPAR 1 LPAR 3 LPAR 2 Application Zone Application Zone Data Zone PR/SM? A HiperSocket is a LAN segment. Treat is like one. 10
Multi-zone networks 11
Multi-zone Network DMZ / Applications db Data network A DMZ (demilitarized zone) is the name given to the subnet that insulates critical network components (servers) from a public network. 12
Multi-zone Network on System z Web / DMZ Applications db Data System z network 13
Firewalls Where, oh, where has my firewall gone? 14
Inboard (internal) firewalls data System z data data Internet 15
Outboard (external) firewalls data data data Internet 16
Guest LANs with HiperSockets LPAR 1 LPAR 2 z/vm z/os DB2 PR/SM HiperSockets Internet = Firewall Router 17
HiperSockets & z/os packet filters LPAR 1 LPAR 2 z/vm z/os DB2 Comms Server packet filter PR/SM HiperSockets Internet = Firewall Router 18
19 Virtual Switches and VLAN Separation
VLAN-unaware VSWITCH Linux1 SET VSWITCH FLOOR2 Linux2 GRANT LINUXn Linux3 Linux4 Virtual access port FLOOR2 Physical access port on VLAN 10 Cisco Corp 20
VLAN-aware VSWITCH SET VSWITCH FLOOR1 Linux1 GRANT FIREWALL Firewall PORTTYPE TRUNK Linux3 VLAN 10 20 SET VSWITCH FLOOR1 GRANT LINUX3 PORTTYPE ACCESS VLAN 20 Virtual trunk port Virtual access port FLOOR1 VLAN 10 VLAN 20 Physical trunk port Cisco Corp 21
Access vs. Trunk 80 00 20 7A 3F 3E Destination MAC 80 00 20 20 3A AE Source MAC 08 00 Type IP, ARP, etc. Payload 00 20 20 3A CRC Ethernet Header 14 bytes Data 46-1500 bytes Ethernet Type II Frame Trailer 4 bytes 64 1518 bytes Access port and Trunk port When used on a trunk port, the switch will associate it with the native VLAN ID (VID) 80 00 20 7A 3F 3E Destination MAC 80 00 20 20 3A AE Source MAC 81 00 TPID 000A VID 08 00 Type IP, ARP, etc. Payload 00 20 20 3A CRC Ethernet Header 14 bytes Data 46-1500 bytes Tagged Ethernet Type II Frame (discarded by access port) Trailer 4 bytes 68 1522 bytes Trunk port 22
Network with VSWITCH (fully shared) LPAR 1 LPAR 2 z/vm db db db z/os DB2 VSWITCH To internet With 1 VSWITCH, 3 VLANs, and a multi-domain firewall 23
Multi-zone Network with VSWITCH (red zone physical isolation) LPAR 1 LPAR 2 z/vm db db db z/os DB2 VSWITCH INTERNET APPDATA To internet With 2 VSWITCHes, 3 VLANs, and a multi-domain firewall 24
25 Enforcing the Separation
Turn off backchannel communications No user-defined Guest LANs VMLAN LIMIT TRANSIENT 0 No virtual CTC MODIFY COMMAND DEFINE IBMCLASS G PRIVCLASS M No IUCV Use explicit IUCV authorization in the directory, not IUCV ALLOW or IUCV ANY No secondary consoles MODIFY COMMAND SET SUBCMD SECUSER IBMCLASS G PRIVCLASS M But what else might there be? 26
Turn off backchannel communications VMCF MODIFY DIAGNOSE DIAG068 IBMCLASS G PRIVCLASS M ESA/XC mode address space sharing DCSS And we can add new interfaces in an APAR Google less than class g by Rob van der Heij Too hard for some folks Consider RACF Mandatory Access Controls instead AppArmor and SELinux provide the same capabilities for Linux 27
Multi-Zoning with RACF Mandatory access controls override end user controls Users are assigned to one or more named projects Minidisks, guest LANs, VSWITCHes, and VLAN IDs, NSSes, DCSSes, spool files all represent data in those same projects Users can only access data in their assigned projects Overrides user- or admin-given permissions 28
Multi-Zoning with RACF A Security Label combines the concepts of Security clearance (secret, top secret, eyes only) Information zones Information zones ly to any place data may exist disks, networks, and other users Security clearance Ensures servers cannot see extra-sensitive data in their information zone Prevents copying of data to medium that is readable by servers with lower security clearance ( No write down ) Not prevalent since there is no equivalent in distributed networking solutions Label dominance is established based on intersection of zones and security clearance Not just a simple string comparison 29
Multi-zone z/vm LPAR with RACF Security Label Enforcement Backup Linux 1 Linux 4 Linux 2 Linux 3 Linux 5 CMS 30
Multi-Zoning with RACF Create security levels and data partitions RDEFINE SECDATA SECLEVEL ADDMEM(DEFAULT/100) RDEFINE SECDATA CATEGORY ADDMEM(DMZ APPS DATA) RDEFINE SECLABEL RED SECLEVEL(DEFAULT) ADDCATEGORY(DMZ) UACC(NONE) RDEFINE SECLABEL GREEN SECLEVEL(DEFAULT) ADDCATEGORY(APPS) UACC(NONE) RDEFINE SECLABEL BLUE SECLEVEL(DEFAULT) ADDCATEGORY(DATA) UACC(NONE) 31
Multi-Zoning with RACF Assign virtual machines their SECLABELs PERMIT BLUE CLASS(SECLABEL) ID(LINUX1) ACCESS(READ) ALTUSER LINUX1 SECLABEL(BLUE) PERMIT RED CLASS(SECLABEL) ID(LINUX2) ACCESS(READ) ALTUSER LINUX2 SECLABEL(RED) 32
Multi-Zoning with RACF But sometimes a server serves the Greater Good, providing services to all users Exempt server from label checking Assign predefined label SYSNONE PERMIT SYSNONE CLASS(SECLABEL) ID(TCPIP) ACCESS(READ) ALTUSER TCPIP SECLABEL(SYSNONE) 33
Multi-Zoning with RACF Example: Assign labels to resources VMMDISK: Minidisk VMLAN: Guest LANs and Virtual Switches RALTER VMMDISK LXHTTP01.191 SECLABEL(RED) RALTER VMMDISK LXHTTP01.201 SECLABEL(RED) RALTER VMLAN SYSTEM.INTERNET SECLABEL(RED) RALTER VMLAN SYSTEM.APPDATA SECLABEL(SYSNONE) RALTER VMLAN SYSTEM.APPDATA.0010 SECLABEL(BLUE) RALTER VMLAN SYSTEM.APPDATA.0020 SECLABEL(RED) PERMIT SYSTEM.APPDATA.0010 CL(VMLAN) ID(LINUX1) ACC(UPDATE) PERMIT SYSTEM.APPDATA.0020 CL(VMLAN) ID(LINUX2) ACC(UPDATE) 34
Multi-Zoning with RACF Activate RACF protection SETROPTS CLASSACT(SECLABEL VMMDISK VMLAN) SETROPTS RACLIST(SECLABEL) SETROPTS MLACTIVE(WARNINGS) If resource doesn t have a seclabel, message is issued and seclabels are ignored. Or SETROPTS MLACTIVE(FAILURES) If resource doesn t have a seclabel, command fails. This is more secure! 35
Summary Check network design with network architect Place firewalls where the network security team wants them to go Use common sense Protect the hardware Protect your data Protect your servers Protect your company Protect yourself!! 36
Reference Information This presentation http://www.vm.ibm.com/devpages/altmarka/present.html z/vm Security resources http://www.vm.ibm.com/security z/vm Secure Configuration Guide http://publibz.boulder.ibm.com/epubs/pdf/hcss0b30.pdf System z Security http://www.ibm.com/systems/z/advantages/security/ z/vm Home Page http://www.vm.ibm.com 37
Contact Information IBM Alan C. Altmark Senior Managing IT Consultant IBM Systems Lab Services and Training z/vm & Linux on System z 1701 North Street Endicott, NY 13760 Mobile 607 321 7556 Fax 607 429 3323 Email: alan_altmark@us.ibm.com Mailing lists: IBMTCP-L@vm.marist.edu IBMVM@listserv.uark.edu LINUX-390@vm.marist.edu http://ibm.com/vm/techinfo/listserv.html 38